'“A lot of synthetic biology is motivated by this idea that … you only understand something when you can build it,” said Johns Hopkins computational biologist Joel Bader, one of the leaders of the project. “Well, now we know enough about biological systems that we can design a chromosome on a computer, synthesize it in a laboratory, put it in the cell, and it will work.”

'Scientists have built designer cells in the past. In 2010, scientists at the J. Craig Venter Institute created a bacterial cell controlled by a synthesized genome by copying the DNA of one bacterium into another. Last year they took the effort a step further by building the first “minimal cell,” an organism never found in nature that had the smallest number of genes required for life. Several months later, a team led by researchers at Harvard Medical School successfully re-engineered a small fraction of the genes of the bacterium E. coli.'